Laser Beams Detect Blood Glucose In Early Experiments

Now, diabetes patients have to endure the pain of needles to get readings of their blood glucose levels: image via 1st-in-diabetessupplies.blogspot.com

For millions of people with diabetes, daily finger pricking with
needles in order to get a measurement of their blood glucose is an
accepted, but unpleasant,
part of their lifestyles. Though physicists have been trying to come up
with laser beam technology that effectively substitutes for the needle,
the accomplishment has evaded them for the past 20 years. Now,
physicists at the University of Toronto (UT) have found a way to get
around the most prickly problem with using a laser beam....

The prickly stickler is that a single beam picks up more than just blood. It also picks up elements that hang out in the blood, like water, which makes up most of blood's volume. But water soaks up the mid-infrared light that is used, just as blood does, and the two elements cannot be separated.

The UT physicists, however, came up with the brilliant idea of using two infrared lights with slightly different wavelengths - one which is absorbed by water and glucose, the other only by water. Both beams strike the glucose, but the beams cancel out each other, and the absorbed water produces enough heat that only the glucose is spotlighted.

Though the technique has not been tested on humans, it has been successfully tested on human blood serum. and it has been found to be sensitive to very small amounts of blood. Though critics note that the laser technique still has a long way to go to prove itself as a substitute for the needle, this two beam technique is a big step.

“Having a noninvasive way to measure glucose has long been a holy grail for
our community,” Andreas Mandelis, an applied physicist at the University of
Toronto, told Science News. The description of his team's research will be published in an upcoming issue of
Physical Review E.